Minolta Autocord allows winding between frames

[OAPOli]

I have a slight issue with my Autocord. I can get a perfectly spaced roll but one can wind the film before the shutter is actuated. The arm that locks the winder after the counter-clockwise action (the one with the signal flag) doesn't go far enough towards the left.

If I release the shutter it moves to the right and locks via the hook just above, as expected.

I thought the issue was not enough tension on the spring just right of the pivot. But a tight spring there disrupts the entire mechanism. I don't see the other way to push the arm further.

 

[Andreas Thaler]

Maybe resistance due to friction?

 

[OAPOli]

Maybe resistance due to friction?

Thanks. The pivot moves with ease.

 

[Dan Daniel]

Camera is in a weird liminal state. Burn some sage and dance... oh wait, wrong forum...

1 in the image is in between. 'Start' is where the shutter release pushed '1' down, causing the upper part of 1 to move left to right. This pulls the upper part of Z/A away from the wind gear- in between shots Z should be to the left, with notch going underneath the gear and locking the wind system. But your shot is not doing this.

And it is also not held to the right by Y dropping into the notch. This happens when the shutter release pushes 1 and its upper arm moves left to right and moves Z/A to the right.

So either your photo was taken at a weird time. Or the upper arm on 1 is too far to the right, keeping Z/A from dropping into gear and locking wind lever.

 

[dxqcanada]

I find it suspicious that the top of this lever has developed a notch

 

[OAPOli]

Thanks @Dan Daniel

The picture was taken after winding and cocking, put before the shutter was released. The whole Z/A hangs there and nothing is pushing it to lock the main wind gear. Indeed the upper arm of 1 could pivot further, but even if I manually move it, Z/A stays put. Is the spring on the right supposed to provide the force? But if that spring is too tight the arm above Y cannot fall into the indexing notches and I can wind forever.

When I release the shutter upper 1 pushes the pin, Y pivots and A falls into the notch.

@dxqcanada the lever is smooth, no notch.

 

[Dan Daniel]

What happens if you push the slotted part hiding behind 1 toward the lens? Push it to the top of the camera with a little screwdriver or such. It is very common for the rings around the shutter block to get gunked up with oil and grease migrating out of the focus helical and binding up the operation of this part.

And check what dxqcanada is seeing for a burr or such binding up travel of Z/A.

Anyway, Z/A needs to drop underneath gear to stop winding (there is a second level of gear teeth under there). You need to find out what is stopping that. The upper arm of 1 needs to move to the left to let that notch get into the gear teeth to stop the winding.

 

[OAPOli]

If I push up the slotted piece upwards it pivots 1 towards the left. It then comes back due to the spring pulling below. Pretty snappy. It likely should pivot further for the Z/A pin to clear. But Z/A has not enough tension from it's own spring (the middle one).

I think there is a delicate balance between these two springs that was upset. I think middle spring is too weak and/or bottom spring is too strong. If I swap them the winder will lock but the shutter release won't unlock.

Is there a source for tiny extension springs?

 

[Dan Daniel]

Can you tell if the slotted tab coming behind the mechanism from the shutter block area is gummed up? If it is, the first thing I would do is go in there and clean out that mess. This means removing the lens shroud and the shutter itself.

 

[OAPOli]

It looks pretty clean but it's hard to be sure.

 

[Dan Daniel]

It's the motion that matters. Remove the piece 1 on the winding board. Get a thin feeler in the opening and check if it moves freely. This will vary based on whether the shutter is cocked or not, '1,' and study the motion of that slotted tab. It's the upward motion that is the issue. You can fake operation of 1 manually. Make certain that it is the spring that stops 1's motion and prevents Z/A from moving left to stop winding motion. It could be the motion of this slotted part that is the problem, and then you need to open up the front and clean that area out.

 

[OAPOli]

Thanks @Dan Daniel

I managed to fix it. I gave a almost imperceptible bend to the L-shaped arm which was preventing Z/A to move to the left and put back the original middle spring for the correct tension. Releasing the shutter frees the slotted tab under the L, spring pulls it down, Z/A locks to the right.

 

[Kino]

Dan's the man for TLRs.

 

[Andreas Thaler]

@Dan Daniel

An excellent demonstration of how to address mechanical problems.

Respect